Positive urinary cytology in patients with lung cancer in the absence of obvious urine tract metastases

Purpose

To study the phenomenon of positive urine cytology in patients with lung cancer in the absence of obvious urothelial metastases.

Patients and methods

150 patients with small (SCLC) and non-small cell lung cancer (NSCLC) of all stages and 3 control groups were prospectively studied. Immunocytochemical study (cytokeratins 7-20, TTF1) in all positive urine specimens and chemokine profile (CXCR4, CCL21) study of the primary tumor in selected positive patients was performed. In experimental study, C57Bl/6 BALB/C mice injected with LLC lung and 4T1 mammary cancer cells were used for the detection of positive urine cytology.

Results

11% of patients with NSCLC, 7% of patients with SCLC and none of the control group had positive urine cytology. In NSCLC, metastatic disease and high tumor burden positively correlated (p = 0.01 and 0.03 respectively) with the phenomenon. In SCLC, correlation with extensive disease and multiple metastatic sites (p = 0.02 and 0.04 respectively) was found. No correlation was found in either group with: age, gender, histology, performance status, line of chemotherapy, previous platinum-based chemotherapy, adrenal metastases, renal function, abnormal urinary sediment, response to chemotherapy and overall survival (p = 0.9). Distinctive chemokine expression was identified in positive patients studied and was not observed in negative patients (×2 p = 0.008). In the experimental study, only the LLC lung cancer cells were detected in the urine cytology of mice.

Conclusion

This phenomenon, carrying undefined pathophysiological mechanisms, seems to characterize only patients with metastatic/extensive disease and high tumor burden. Further studies are needed to validate our preliminary chemokine expression results.